magnusson



March 10, 964 K. J. MAGNUSSON 3,124,434

' ELECTROSTATIC PRINTING APPARATUS Filed March 27, 1962 3 Sheets-Sheet 111 11 II 1111 I 1 I I I I I I I l I I 1 I I I I I 1 I 1 I I I I I 11INVQNEOR. Mar 1 Maw/11a March 10, 1964 K. J. MAGNUSSON ELECTROSTATICPRINTING APPARATUS 3 Sheets-Sheet 2 Filed March 27, 1962 I N VEN TOR. KwJ Mil/M10 9 2 lt/l/fl/V March 1964 K. J. MAGNUSSON ELECTROSTATICPRINTING APPARATUS 3 Sheets-Sheet 3 Filed March 2'7, 1962 INVENTOR. 7' jMIA V 1 Immu/ 3,124,484 Patented Mar. 10, 19 64 ELECTROSTATIC PRINTINGAPPARATUS Knot J. Magnusson, Princeton, N.J., assignor to RadioCorporation of America, a corporation of Delaware Filed Mar. 27, 1962,Ser. No. 182,881 6 Claims. (Cl. 118-637) This invention relatesgenerally to improved electrostatic printing apparatus and particularlyto such apparatus including improved means for applying liquid developercompositions to an image bearing web or the like.

In the art of electrostatic printing, electrostatic images are producedon the surface of an insulating materiah Such images comprise a patternof electrostatic charges on the surface. Visible images are commonlyproduced therefrom by applying across the surface a dry mixture offinely-divided developer particles and substantially larger carrierparticles. charged areas to produce a visible image in substantialconfiguration with the pattern of charges. Several meth ods of producingvisible images are described in Electrofax Direct ElectrophotographicPrinting on Paper, by

C. J. Young and H. G. Greig, RCA Review, December 1954, vol. XV, No. 4.

'The recording element'maycomprise almost any insulating surface but,preferably, the recording surface is also photoconductive to enable therecording of light images. Recording elements comprising.photoconductiveselenium coated plates are described in U.S. Patent 2,297,691, issuedOctober 6, 1942, to C. F. Carlson. Recording elements comprisingphotoconductive coatings on paper are described in the aforementionedYoung and Greig publication.

A so-called liquid process for developing electrostatic images has beenproposed in which the solid developer particles are suspended in aninsulating carrier liquid. Liquid development methods provide manydistinct advantages over the use of dry developer mixtures and othermethods of developing electrostatic images for some applications.Basically, the liquid developer consists of finelydivided developerparticles dispersed in an insulating liquid. This developer can beflowed over a surface bearing an electrostatic image or the surface canbe immersed in a tray of liquid developer. It can also be sprayed orrolled onto the surface. A liquid developer process for charge images isdescribed in greater detail by K. A. Metcalfe and R. J. Wright in apaper entitled I Xerography, published in the Journal of the Oil andColour Chemists Association, November 1956, vol. 39, No. 11, London,England, and in another paper entitled Liquid Developers for Xerography,published in the Journal of Scientific Instruments, February 1955, vol.32.

Although the above-mentioned liquid development processes are suitablefor many purposes, it has been found that they have at least one seriousdeficiency. When producing a visible image by deposition of developerparticles from a liquid onto a charged surface, particles adhere in thebackground areasas well as in the image areas on the surface. Backgroundareas are those areas on the surface bearing little or no electrostaticcharge and hence, are those areas in which deposition of developerparticles is unwanted. Such spurious deposition in nonimage areasresults in a spotted or mottled background on the finished print which,in many applications, is unsatisfactory. This efi'ect is even morepronounced when attempting to reproduce fine detail. The morefinely-divided the developer particles are, the greater the spuriousdeposi:

tion in background areas.

-In addition to the foregoing deficiency, it has been found that whenimages are developed with a liquid composition carried on a roller,second and subsequent rota- United States Patent Office The developerparticles deposit in A tional cycles of the roller cause ghost images tobe offset printed on a recording medium by the roller. Considerable caremust be exercised in applying the liquid developer dispersion to thedeveloper roller to provide a uniform distribution of developer thereonto obviate streaking of the developed image, which may occur when aplurality of jets are employed to apply developer to the roller.

It is a general object of this invention to provide improvedelectrostatic printing apparatus.

A further object of this invention is to provide improved apparatus forapplying liquid developer compositions to electrostatic images.

Another object is to provide improved means for more uniformly applyingliquid developer to roller apparatus members with substantial reductionor elimination of undesirable offset printing of ghost images thereon.

These and other objects are accomplished in accordance with thisinvention which provides electrophotographic apparatus including meansfor charging the surface of an electrophotographic member, means fortransporting the member through an exposure region, a developermechanism adjacent the exposure region comprising a developer rolleradapted to have the electrophotographic member contact therewith andmeans for uniform- 1y applying liquid developer composition to saidroller in a manner to substantially reduce or eliminate offset printingor ghost images deriving from the previous development of the precedingelectrostatic images, and to minimize streaking or non-uniformity in thedensity of the developed image. The desired uniformity in theapplication of the developer to the roller is insured by means of acontinuous fountain or fan jet of developer extending continuouslyacross substantially the entire width of the developer roller.

Other objects and advantageswill be apparent from the following detaileddescription to be read with reference to the accompanying drawingswherein:

FIGURE 1 is a front, cross-sectional view taken along the section line1-1 of FIG. 2 of the interior of an electrostatic printing apparatusmade in accordance with this invention;

FIGURE 2 is a side, cross-sectional view of the interior of theapparatus of FIG. 1 taken along the line 22 thereof;

FIGURE 3 is a side cross-sectional view of the developer mechanism ofFIG. 2;

FIGURE 4 is a perspective partially cut-away View of I paratus isdesigned with a portion of the top of the housing thereof forming aninverted .V-shaped roof. This V-shaped structure is adapted, as shown,to support a book 11 so that a page thereof 'which is to be copied is incontact Witha transparent plate '13. A hinged platel4 is provided toinsure that the page to be copied is firmly held against the transparentplate 13. A single sheet, such as a letter, could be equally-well heldin place by the hinged plate 14. The page of the book is illuminatedthrough the transparent plate 13 by means of a light source 15 and areflector 1-7.

suggest The light source 15 may comprise one or more pencil shapedhorizontal lamps. Well suited for the purpose are la'rnps such as 500watt tungsten filament quartz tubes which contain traces of iodine. Theiodine in the lamp functions to catch tungsten particles which evaporateduring operation and to return those particles to the filament. Such alamp is produced by the General Electric Company, catalogue No. 500T3Q/CL. The reflector 17 conveniently comprises a segment of a 6" hollowcylinder, the inside of which is polished to a high degree. Since thedistance from the light source 15 to the bottom edge of the plate 13 ismuch less than the distance of the light source 15 to the top edge ofthe plate 13, the reflector 17 is positioned to concentrate reflectedlight toward the upper portion of the transparent plate 13 so that theentire area under the plate is uniformly illuminated. In addition, ifrequired, a properly shaped screen 16 or absorber 18, in the direct orreflected paths respectively of the illumination, may be used to improveillumination uniformity on the page to be copied.

Light reflected from the page of the book 11 is concentrated through alens system 19 to impinge upon the mirror 21. The light is thenreflected from the mirror 21 upwardly and focused on an exposure plane23. If desired, a shutter 24 is provided in the light path between themirror 21 and the exposure plane 23 in order to prevent any ambientlight from reaching the exposure plane except when exposure is desired.

Further details of the internal structure of the compartment 27 areillustrated in FIGURE 2. A supply roll 29 of photosensitive webbing ismounted in the lower portion of the compartment 27. The webbing 30 onthe supply roll may comprise, for example, electrophotographic papersuch as is described in the aforementioned Young and Greig Publication.The paper 30 is fed from the supply roll 29 over an idler roller 31through a double corona charging apparatus 33 and into the exposureplane 23. The paper is then carried partly around one flexible surfaceroller 25 of a pair of pressure rollers in a manner so that it reversesits direction and is then brought out from the copier apparatus under aheat fusing mechanism 28.

In the apparatus as shown in FIGURE 2, the double corona charging unit33 may comprise two opposed structures of very fine parallel wires asdescribed in US. Patent 2,922,883, issued to E. C. Giaimo, Jr., onJanuary 26, 1960, and the heat fuser 28 one such as is described in US.Patent 2,857,682 to R. G. Olden et al. on October 28, 1958.

From the charging apparatus 33 the paper 30 is transported into theexposure plane 23 with its photosensitive surface facing downward. Whilethe paper is maintained stationary in the exposure plane 23, thecharging unit is energized and traverses the paper forwards and back tothe position shown. After charging is completed, the light source isenergized for desired exposure time, and the light image reflectedupward from the mirror 21 to substantially reduce or eradicate thecharges placed on the paper by the corona unit 33 in those areas onwhich light impinges. As the paper 30 subsequently passes over one ofthe pressure rollers 25, liquid developer composition from liquiddeveloper unit 35 is applied to the other pressure roller 26, which inturn applies the liquid developer composition to the paper 30 toproduce, in those areas thereon which were not struck by light, avisible image of developer material. This visible image is then fixed tothe surface of the paper as it passes under the fuser 28.

In FIGURES 3 and 4, the developing unit 35 of FIG. 2 is illustrated ingreater detail. This developer unit includes the two pressure rollers 25and 26 which engage the paper and which are driven to pull the paperfrom the supply roller 29 (FIG. 2) through the projection plane 23 shownin FIGURE 2. Liquid developer composition is applied to the upperpressure roller 26 by means of the applicator 41, described in detailhereinafter. The developer composition is supplied to the applicator 41through a pipe 43 ('FIG. 3) connected to a centrifugal pump 45. Asliquid developer composition is carried by the upper pressure roller 26into contact with the paper, a turbulent nip 46 of the developercomposition is formed where the roller 26 contacts the paper. Thisturbulent nip 46 of developing composition substantially enhancesdevelopment of images on the paper and also enhances clean-up ofdeveloper material which may adhere in unwanted areas on the paper 30.The liquid developer composition not only forms the nip 46 but alsoflows down the surface of the paper 30 as it is carried over thepressure roller 25. The developer composition is thereby caused to be incontact with a substantial portion of the paper 3% as it is transportedover the roller 25.

Developer composition in excess of that used to develop an image on thepaper drops therefrom into a tray or sump 47 positioned below the twopressure rollers 25 and 26. The developer composition collected in thesump 47 is returned to the developer container 4-4 through a pipe 49,which preferably surrounds the feed pipe 43.

A preferred form of the applicator 41 includes a metallic head havingits upper surface and ends curved to conform to the surface of the upperpressure roller 26 to provide a seal for the liquid developerdispersion. The applicator 41 has a length slightly shorter than thelength of the pressure roller 26. An elongated U-shaped slot 42extending almost the full length of the applicator 41, and centeredtherein, opens at the lowest point 42' thereof into the developer supplypipe 43. The applicator 41 is supported in the developer assembly 35 byflat pressure springs, 51 and 53, which press the applicator firmlyagainst the surface of the roller 26. The face 55 of the applicator 41adjacent the lower edge of the pressure roller 26 is undercut about .005inch as shown in the detailed illustrations thereof in FIGURES 6, 7 and8. The precise depth of undercut required is dependent upon developerpump capacity in order to insure that developer continuously fills theslot and undercut openings. Thus, while the upper surface 57 and theends 59 of the lower adjacent surface are in close proximity to the faceof the roller 26, the developer is applied extremely uniformly and withthe desired pressure to the lower face of the pressure roller 26 alongsubstantially its entire length.

After the developer has been carried by the upper roller 26 to developthe electrostatic image on the paper 30, the developer runs down thesurface of the paper, as indicated by the stippling in FIG. 3, until itreaches the wiper seal 61. The wiper seal 61 comprises a member, forexample, of Teflon, bevelled to conform to the surface of the papercarried by the lower pressure roller 25. It is pressed against the lowersurface of the paper by one or more flat or coiled springs 63 supportedin a bracket 65 attached to the side of the sump 47. Excess developercollected in the bottom of the sump 47 is returned to the developerreservoir 44- through the return pipe 49.

FIGURE 5 shows a modification of the developer applicator element 41wherein the applicator 4.1 is shaped to conform to the curvatures ofboth pressure rollers 25 and 26 to provide end seals therewith for thedeveloper solution after it is first applied to the upper roller 26 andafter it cascades down the surface of the paper around the roller 25. Asan alternative, the return pipe 49 for the excess developer is separatefrom and not coaxial with the supply pipe 43.

An important feature of the developer units described by reference toFIGS. 3 to 8 is that they comprise substantially closed systems fordeveloping images on the paper 30. Such closed systems make it possibleto use developer compositions which include a highly volatile liquidWithout resulting in excessive evaporation of that liquid. Excessiveevaporation would ultimately result parts solution in wide variations inthe concentration of the developer material in the developercomposition.

An example of a suitable, highly volatile developer composition is onewherein finely-divided electroscopic developer particles are dispersedin a liquid carrier of trichlorotri'fluoroethane.

Example A black pigment is prepared bymaking two solutions.

Solution 1 comprises: Grams Iosol Black (Cl. Solvent Black 13) 6Methanol 400 Solution 2 comprises:

Spirit Nigrosine (CI. 50415) 9 Methanol 400 to 600 Solution 1 is pouredinto solution 2 with continuous stirring. Once the solutions have beenthoroughly mixed and a black, relatively insoluble pigment isprecipitated, the mixture is filtered and the filter cake allowed todry. The dried filter cake is broken up and dispersed in dimethylpolysiloxane liquid having a viscosity of about 2 centistokes. Theproportions in this dispersion are about 1 to 10 parts black pigment toabout parts of liquid. It is preferred that the liquid content be keptas low as possible but sufi'icient'to provide ,a uniform dispersion.After ball milling the black pigment is classified as to particle size.Particles having a diameterof 74 microns or less are preferred.

Also prepared is a solution consisting of:

Grams Dimethyl polysiloxane (silicone) 200 Trichlorotrifiuoroethane(Fre0n). 200

About one part by weight pigment dispersion per 10 is added to provide afinal developer composition.

As images are developed on the paper with the apparatus, theconcentration of developer particles in the container 44 may becomedepleted at a greater rate than will the liquid carrier portion thereof.In order to maintain the proportions of components in the liquiddeveloper at a substantially constant level, means are provided forinjecting into the container 44, metered amounts of a concentrateddeveloper composition. The developer concentrate is contained in a jar67. A reciprocating pump 69 is inserted in the jar 67 andis powered by asolenoid 71. At each stroke of the pump 69 in the jar 67 a smallquantity of developer concentrate is forced through the pipe 73 andinjected into the container 44. It is desirable that the reciprocatingpump 69 be provided with an adjustable stroke whereby the quantity ofdeveloper concentrate injected each time into thecontainer 44can beregulated. It is also desirable that the solenoid be energized,ifdesired, each exposure cycle or'if desired once each two cycles or oneeach five cycles or so.

A suitable developer concentrate may be prepared by dispersing developermaterial such as that described heretofore in a dimethyl polysiloxane ina proportion of about 20 parts by weight of developer material to 80parts by weight of a dimethyl polysiloxane having a viscosity from 0.6to about 3 Centisto kes.

What is claimed'is: I

1. Apparatus for applying liquid developer composition to a continuousweb bearing a latent electrostatic image, said apparatus comprising:

(a) liquid developer supplying means,

(12) a pair of pressure rollers adapted to contact op posite surfaces ofsaid web, one of said rollers being adapted to have said web contact asubstantial por- 6 and providing means for bringing liquid developercomposition into contact with said Web, (0) means providing a continuouscolumn of said liquid developer extending transversely substantiallyacross said other roller for applying said liquid developer compositionto said other roller to develop said latent image on said web and tosubstantially obliterate offset images formed on saidother roller as aresult of previous development of electrostatic images on said web withsaid other roller,

(d) said liquid applying means comprising an element having one edgesurface and adjacent end surfaces contacting said other roller andshaped to conform to the curvature thereof, and having another undercutedge surface between said end surfaces closely spaced from said otherroller along a substantial portion of its length, and a longitudinalslotted portion between each of said surfaces, said slotted portioncommunicating with the developer supply means, f

and (e) means for rotating said rollers and moving said webtherebetween.

2. Apparatus for applying liquid developer composition to a continuousweb bearing a latent electrostatic image, said apparatus comprising:

(a) liquid developer supplying means,

(b) a pair of pressure rollers adapted to contact opposite surfaces ofsaid web, one of said rollers being adapted to have said web contact asubstantial portion of the periphery thereof, the other of said rollersbeing positioned in'a plane above said one roller so as to makesubstantially line contact with said web and providing means forbringing liquid developer composition into contact with said web,

(0) means providing a continuous column of said liquid developerextending transversely substantially across said other roller forapplying said liquid developer composition to said other roller todevelop said latent image on said Web and to substantially obliterateoffset imagesformed on said other roller as a resultof previousdevelopment of electrostatic 7 images on said web with said otherroller,

(:1) said liquid applying means comprising an element having one edgesurface and adjacent end surfaces contacting said other roller andshaped to conform to the curvature thereof, and having another undercutedge surface betweensaid end surfaces closely spaced from said otherroller along a substantial portion of its length, and a longitudinalslotted portion between each of said surfaces, said slotted portioncommunicating with the developer supplying means, g

a (e) spring actuated means for biasing said surfaces to contact saidother roller, and

(f) means for rotating said rollers and moving said web therebetween.

3. Apparatus for applying liquid developer composition to a continuousweb bearing a latent electrostatic image, said apparatus comprising:

(a) liquid developer supplying means,

(b) a pair of pressure rollersadapted to contact 0p posite surfaces ofsaid web, one of said rollers being adapted to have said web contact asubstantial portion of the periphery thereof, the other of said rollersbeing positioned in a plane above said one roller so as to makesubstantially line contact with said web and providing means forbringing liquid developer composition into contact with said web,

(0) means providing a continuous column of said liquid developerextending transversely substantially across said other roller forapplying said liquid developer composition to said other roller todevelop said latent image on said web and to substantially obliterateofi'set images formed on said other roller 7 as a result of previousdevelopment of electrostatic images on said web with said other roller,

(d) said liquid applying means comprising an element having one edgesurface and adjacent end surfaces contacting said other roller andshaped to conform to the curvature thereof, and having another undercutedge surface between said end surfaces closely spaced from said otherroller along a substantial portion of its length, and a longitudinalslotted portion between each of said surfaces, said slotted portioncommunicating with the developer supplying means,

(e) wherein said element includes other end surfaces for contacting saidweb on the periphery of said one roller and shaped to conform to thecurvature of said one roller, and having a second undercut edge surfacebetween said other end surfaces closely spaced from said web, and

(f) means for rotating said rollers and moving said web therebetween.

8 (b) drive means for rotating said rollers to move said webtherebetween, (c) applicator means for applying liquid developercomposition to said other roller in a continuous column extendingtransversely substantially across said web to develop said latent imageand with sufficient force to substantially obliterate offset imagesformed on said other roller as a result of previous development ofelectrostatic images on said web with said other roller,

(a') container means for a supply of said liquid de- Nelopercomposition,

(e) pump means for drawing liquid developer composition from saidcontainer means and supply it to said applicator means under pressure,and

(f) sump means positioned below said rollers for collecting excessdeveloper composition and returning it to said container means.

6. Apparatus for applying liquid developer composi- 4. Apparatus forapplying liquid developer composition to a continuous web bearing alatent electrostatic image, said apparatus comprising:

(a) liquid developer supplying means,

(b) a pair of pressure rollers adapted to contact option to a continuousweb of electrophotographic material bearing a latent electrostaticimage, said apparatus comprising:

(a) a pair of pressure rollers adapted to contact opposite surfaces ofsaid web, one of said rollers being P0site surfaces of one Of SaidP011659 being adapted to have said web contact a substantial porp t0 Y531d Web Contact a substaqtlal P tion of the periphery thereof, theother of said rollers tion of the periphery thereof, the other of saidrollers being positioned in a Plane above said one Toner so bemgPosmoned m above said rqller so as to make substantially line contactwith said web, as to malfe substantially 11116 contact Wtth Sa W65 (b)drive means for rotating said rollers to move said and providing meansfor bringing liquid developer web therebetween composmon m? Contact,Wlth sald (c) applicator means for applying liquid developer (C) meansY a cfmtmuous column of sa1d composition to said other roller in acontinuous coluld dewfoper transvelsely ,subta1}t1auy umn extendingtransversely substantially across said across Sald applymg Sald hquldweb to develop said latent image and with sufficient veloper compositionto said other roller to develop force to substantially obliterate offsetimages formed latent on Sald web and 9 Substantlany on said other rolleras a result of previous developobliterate offset images formed on saidother roller ment of electrostatic images on said web with said as aresult of previous development of electrostatic other Toner, Images 9.Sald wlth Sald (d) container means for a supply of said liquid de- (d)said liquid applymg means comprising an element 40 veloper compositionhaving one edge surface and ad acent end surfaces (8) pump means,foladrawing liquid developer composi contacting said other roller andshaped to conform vtion from Said container means and supplying it to tothe curvature thereof, and hav1ng another undersaid applicator meansunder pressure and out edge Surfalm between Sald end SurfaCes .Closely(f) sump means positioned below said rollers for col- SPaced F saldother roller along a substantlal lecting excess developer compositionand returning tion of its length, and a longitudinal slotted portion itto Said Container means and between of .Sald Surfaces Said Pomon (g)additional container means for a supply of concomniumcatmg Wlthdeveloper Supplymg. centrated liquid developer composition, and (e)Spnng actuated lmper meians for contactmg Sald (h) means for supplyingmetered amounts of said con- Web on the underilde Sald one roller icentrated composition to said first mentioned con- (f) means forrotating said rollers and moving said miner means web therebetween. 5Apparatus f applying fliq id developer i- References Cited in the fileof this patent tion to a continuous web of electrophotographic materialUNITED STATES PATENTS beain a ltntlt tt" i p g g a 6 e ec ms a 10 ImageSald apparatus com 2 624 14 Rhodes Jam 13 953 (a) a pair of pressurerollers adapted to Contact opg f a? posite surfaces of said web, one ofsaid rollers being {9 J i 1961 adapted to have said web contact asubstantial p01'- 21 O nson u y tion of the e h th 3,008,404 Metcalfe etal Oct. 10, 1961 perip ery ereof, the other of said rollers 01 S h th N28 1961 being positioned in a plane above said one roller so 5 c elmeras to make substantially line contact with said web FOREIGN PATENTS d pi ng m ans for bringing liquid developer 812 013 Great Britain Apr. 15,1959 composition into contact with said web,

1. APPARATUS FOR APPLYING LIQUID DEVELOPER COMPOSITION TO A CONTINUOUSWEB BEARING A LATENT ELECTROSTATIC IMAGE, SAID APPARTUS COMPRISING: (A)LIQUID DEVELOPER SUPPLYING MEANS, (B) A PAIR OF PRESSURE ROLLERS ADAPTEDTO CONTACT OPPOSITE SURFACES OF SAID WEB, ONE OF SAID ROLLERS BEINGADAPTED TO HAVE SAID WEB CONTACT A SUBSTANTIAL PORTION OF THE PERIPHERYTHEREOF, THE OTHER OF SAID ROLLERS BEING POSITIONED IN A PLANE AB OVESAID ONE ROLLER SO AS TO MAKE SUBSTANTIALLY LINE CONTACT WITH SAID WEBAND PROVIDING MEANS FOR BRINGING LIQUID DEVELOPER COMPOSITION INTOCONTACT WITH SAID WEB, (C) MEANS PROVIDING A CONTINUOUS COLUMN OF SAIDLIQUID DEVELOPER EXTENDING TRANSVERSELY SUBSTANTIALLY ACROSS SAID OTHERROLLER FOR APPLYING SAID LIQUID DEVELOPER COMPOSITION TO SAID OTHERROLLER TO DEVELOP SAID LATENT IMAGE ON SAID WEB AND TO SUBSTANTIALLYOBLITERATE OFFSET IMAGES FORMED ON SAID OTHER ROLLER AS A RESULT OFPREVIOUS DEVELOPMENT OF ELECTROSTATIC IMAGES ON SAID WEB WITH SAID OTHERROLLER, (D) SAID LIQUID APPLYING MEANS COMPRISING AN ELEMENT HAVING ONEEDGE SURFACE AND ADJACENT END SURFACES CONTACTING SAID OTHER ROLLER ANDSHAPED TO CONFORM TO THE CURVATURE THEREOF, AND HAVING ANOTHER UNDERCUTEDGE SURFACE BETWEEN SAID END SURFACES CLOSELY SPACED FROM SAID OTHERROLLER ALONG A SUBSTANTIAL PORTION OF ITS LENGTH, AND A LONGTITUDINALSLOTTED PORTION BETWEEN EACH OF SAID SURFACES, SAID SLOTTED PORTIONCOMMUNICATING WITH THE DEVELOPER SUPPLY MEANS, AND (E) MEANS FORROTATING SAID ROLLERS AND MOVING SAID WEB THEREBETWEEN.